The restoration of a hard disk drive, or a partition of a hard disk drive, appears to be a generally complex and tricky procedure, which involves a great number of manual operations. When a hard disk drive suffers a breakdown and needs to be replaced, the user is compelled to enter into a laborious procedure for the purpose of re-establishing the configuration of his machine. He generally has to partition the new hard disk, to format the different partitions, to install the Operating System (OS) within the active partition, be it Windows (a trademark of Microsoft Corp.), Linux or OS/2 (a trademark of IBM Corp.) Once the Operating system has been installed, for instance Windows 98, the user may then take advantage of the internal backup/restore software facility which is incorporated in the OS for the purpose of restoring his data files. In the case of a Windows NT operating system, the user must then re-establish the Network Domain Controller (NDC) and re-trust the machine. When all the data files are restored, the will be completed by the restoring of the appropriate security settings (including the Access Control Lists which contain the list of users having permission to access the files) in the case of the UNIX, Windows NT, or OS/2 operating systems. It is clear that all those manual operations may be well beyond the normal possibilities of the ordinary user.
If the user has a stand-alone computer, he may take advantage of some type of hard disk image software which has revealed to be of much interest for taking and storing an image of a given partition. Such programs, marketed for instance by PowerQuest™ and NORTON™ under the commercial names of Drive image and Ghost, respectively, make a systematic copy of the contents of the clusters of a given partition. The copy of the partition and its restoration are substantially facilitated, since the user and, and the restoration of restore is thus facilitated and the user may get rid of all the manual steps which were mentioned above.
The image creation technique shows to be very useful for restoring an image of a given partition, but not without the cost of some disadvantages. A first drawback clearly results from the fact that, in that approach, a whole partition needs to be copied in one file, thus requiring a substantial storage media for each backup operation. No incremental backup is permitted and there is a need for a substantial amount of storage capacity, even between two successive backup procedures. Further, since the image taking procedure is handled under the DOS operating system, the computer is rendered no longer available for other tasks during a non negligible period. At last, the stand-alone backup procedure reveals to be not well adapted to a corporate environment involving a great number of different computers which are connected in a network. In that situation, the “disk image” approach would require as many image files—each one of a considerable size—as there are different machines comprised in the network. Generally speaking, in a corporate environment, an Information Technology (IT) manager provides the user support and, clearly, an set of individual backup images of all the machines is not feasible. The IT manager generally creates a so-called “Gold” or “Master” image of a typical configuration which contains the Operation System with the appropriate drivers. The gold image can then be used for re-creating, when required, an image of the configuration in one machine, and the restoration of the configuration can then be completed with the reestablishment of the user's files. In the case-of Windows NT again, the machine needs still to be retrusted and the Security Identifier (SID) be redefined. Although the gold image shows to be very useful and substantially facilitates the work of the IT manager when the latter has to re-establish the configuration on an individual machine connected to a network, it appears that manual operations still need to be performed, or at least by a skilled user, for the sake of re-establishing the entire configuration of the machine. At least, the transfer of the image from the “gold” or “master” disk for the purpose of re-establishing a remote access to a backup server implies a manual intervention of the IT manager and that, even when the crash does not result from any hardware breakdown, what is not so rare in the practice of the operating systems. Inevitably, the intervention of the IT manager substantially increases the costs of the computers maintenance.
Therefore there is still a need for a solution which permits to largely automate the backup and restore procedure so that it becomes directly applicable for a large number of operating systems, even when configured in a network or corporate environment, and that without requiring a skilled staff or an IT professional.
It is further desirable that the backup procedure can even take advantage of an Internet network so as to render the procedure fully transparent to the user who may continue to work with his machine. It is additionally expected that the backup procedure is not disturbed by the existence of the firewall arrangements which a company or a private organisation may arrange for securing its network.